ADDremaining 2 cups water. Increase heat to medium-high. When mixture begins to boil, stir in spinach and cook for 1 minute or until wilted. Cool slightly. Transfer half of soup to blender; add half of evaporated milk. Cover and process until smooth. Transfer to bowl. Repeat with remaining soup and evaporated milk. Return soup to saucepan to heat through. Season to taste with salt and ground black pepper.